Change soundTool's behavior so that it does not block code execution

[dllargent]

As currently implemented, the following example code will cause a soundTool window to open for s1, and code execution stops until the soundTool window is closed. At that point, the next line of code is run and a second soundTool window opens for s2.

s1 = makeSound(pickAFile())
s2 = makeSound(pickAFile())
soundTool(s1)
soundTool(s2)

To allow for the possibility of having multiple soundTool windows open so that the sounds may be compared, it will be useful to allow the code execution to continue after opening the soundTool window, rather than stopping execution, as it currently does. This enhancement will match the behavior of pictureTool that allows multiple windows to be open, without stopping code execution.